First of, check out the interview below, in which the Russo brothers talk about Winter Soldier and the next Captain America film (among others, they are almost certain that Chris Evans won’t drop the shield any time soon). It is also interesting how they say that Civil War adaptation isn’t possible because Marvel doesn’t own the rights for all the major characters (as if in the Avengers we also saw Spider-Man and other major superheroes):

The Russo brothers have also said that the story lines for all Captain America movies (and not only) as well as the titles have all been found as far as 10 years ago. Captain America 3, for example, will have to deal with all the ripples created by the fall of HYDRA (the discovery of the double agents and so on, as seen in The Winter Soldier):

“The big thing we knew we had to deal with in Captain America 2 was the fall of Hydra. Similarly there is a very, very big idea at the center of Captain America 3. But how we get there is all up to us. And I think why Marvel has been so successful is because it’s been such a clear plan, that everything is interconnected and they’re building emotional capital with each movie that you can then trade off of in the next film. f you’ve been talking to Kevin Feige, the title has been in place probably for ten years in his brain. It’s all part of the road map that he’s laid out, and it’s all part of the bigger plan. I think the way Kevin does it is there are big pieces that he knows he wants to build towards, but the way that you get there is open to interpretation and improv a little bit. That’s defined by who gets involved with the project, the writers and directors involved in the project.”

Lastly, the directors also said,

”all that stuff is open for interpretation. Usually it’s just one big idea that alters the universe as a whole in some way, that has interconnectedness that he’s grabbed on to. That’s the case with [Captain America 3](movie:994409), but as far as villain and story arc and tone, all that stuff is left up to us [Captain America 3](movie:994409), but as far as villain and story arc and tone, all that stuff is left up to us.”